Experts say that 90 percent of the known species on Earth are smaller than a human finger. We'll talk with zoologist and photographer Piotr Naskrecki about what he calls the "Smaller Majority." It's the title--and subject--of his new book, which chronicles Earth's biodiversity through startling photographs.

Researchers studying the chemical makeup of the atmosphere around Saturn's moon Titan have detected imbalances that, some say, could be signs of life. Jonathan Lunine, a scientist on the Cassini mission to Saturn, says it's too soon to plan a solar-system-wide block party.